Engineered Threaded Fasteners for Plastics

Transcription

1 Engineered Threaded Fasteners for Plastics

2 Fastening & Assembly Solutions for Plastic Applications Plastics continue to open up a world of design opportunities, yet present some unique fastening problems. Whether you re fastening plastic to plastic or plastic to another material, STANLEY Engineered Fastening offers a wide selection of high-performance fasteners engineered to meet the requirements of your application. Why use Special Fasteners for Plastics? Each type of plastic has its own set of performance issues, such as ductility, thermal expansion and clamp retention. Selecting a fastener that can best match these requirements is critical to the overall performance of an application. Type B, type AB and other standard fasteners, with wide flank angles and shallow s, were designed for use in sheet metal and can not meet the dynamic requirements of plastics. Optimal Performance Fasteners specially designed for plastics can optimize performance in specific types of materials. By selecting the proper fastener, you may obtain: Selecting the Right Fastener With thousands of different polymers available today, there can be no absolute guidelines to follow when fastening these materials. Laboratory testing of fasteners in the subject material is the only way to determine if acceptable performance levels can be achieved. For maximum performance, a fastener should be selected early in the design process. STANLEY Engineered Fastening applications engineers are available to help you every step of the way, from selection and testing to boss design. Higher strip-out torque values Increased resistance to loosening Higher pull-out values Reduced In-Place Costs Proper fastener selection may allow the use of thinner bosses and eliminate the need for supplementary locking devices. This can reduce in-place costs through: Reduced material usage Reduced cycling times Elimination of inserts and adhesives Streamlined assembly

3 Engineered Threaded Fasteners for Plastics Table of Contents Threaded Fasteners for Plastics - Threaded Fasteners for Plastics vs. Standard Screws... 4 Joints in Plastics - Properties of Plastics Installing a Threaded Fastener in Plastics Design Issues and Fastener Selection Fastener Selection Chart... 9 Threaded Fasteners for Thermoplastics - Delta PT Fasteners PT Fasteners DST Fasteners PLASTITE 48 Fasteners PLASTITE 45 Fasteners Threaded Fasteners for Thermoset Plastics - Duro PT Fasteners Other Threaded Fastening Solutions - Powergrip Fasteners for Layered Assemblies PlasTORX Fasteners for Molded Assemblies Other Threaded Fasteners for Plastics TORX PLUS Drive System Definitions - Glossary

4 Fasteners for Plastics vs. Standard Screws Standard Fastener 60 S Typical Boss Design for Standard Screw Special Fastener for Plastics / 3 S Typical Boss Design for Fastener for Plastics Narrow Thread Profiles Maximize Performance Type B, type AB and other standard fasteners have a wide profile (also called flank angle) of 60. Special fasteners for plastics have special profiles to meet the needs of these unique materials. These narrower profiles, ranging from 30 to 48, reduce radial stress and expansion. This in turn maximizes fastener performance. Because radial stress is reduced, special fasteners for plastics allow the use of smaller bosses than standard screws, as shown at left. Using smaller bosses can reduce your overall costs through decreased material usage and molding cycle times. Mø 1 Mø 2 CM 1 CM 2 mø 1 mø 2 CM 1 CM 2 mø 1 mø 2 Increased Resistance to Pull-Out In the illustrations at left, CM represents the area subjected to shear when an axial load is applied. Because the special fastener for plastics has a smaller minor diameter (mø) and a higher profile, it contains a larger volume of material (CM) and has a larger axial shear area. This greater area of engagement means the special fastener for plastics is more resistant to pull-out. Standard Fastener Special Fastener for Plastics R 1 FRAD 1 Lowered Radial Stress Prevents Boss Damage 30 FRAD = 0.500R 60 Standard Fastener Radial force (FRAD) is an undesirable force since it creates outward stress and can damage the boss. Although the same volume of material is displaced between the 60 and the 30, the radial force generated by the 30 is approximately one-half that of the 60. R 2 15 FRAD 2 30 FRAD = 0.259R In the photo at right, the plastic boss with a 60 fastener shows radial stress and subsequent damage. The plastic boss with a special fastener for plastics shows reduced radial stress. Standard Fastener Special Fastener for Plastics Special Fastener for Plastics

5 The Properties of Plastics The fastening performance of plastics is affected by several factors: Flexural modulus (stiffness of material) Filler and/or reinforcement content (amount of glass, etc. added to material) Thermal expansion rate Creep rate Flexural Modulus Flexural modulus is the best indicator of how a plastic will respond to fasteners. Generally, the lower the flexural modulus, the more the material will flow and allow the formation of s. Thermoplastics with a higher flexural modulus also allow the formation of s, but usually require a fastener with a low helix angle to avoid excessive drive torque. Plastics with a high flexural modulus, including thermosets, are too stiff for forming and will require -cutting fasteners. There are definite exceptions to these guidelines which can adversely affect fastening performance. Involve our application specialists early in the design process to maximize joint reliability. Tensile Strength Clamp Load (lbs.in) Strain (% Elongation) Time (min.) The Effects of Fillers on Fastening Fillers and reinforcements change one or more properties of the thermoplastic. They can also affect fastening performance. For example, impact-resistant resins tend to act more ductile than their flexural modulus would indicate. Lubricants added for molding, such as silicone, tend to reduce drive torque but can negatively affect clamp load. Again, it is important to test your application early in the design process to ensure optimal performance. Thermal Expansion Rate The stress/strain curve for thermoplastics is very temperature dependent. Plastics expand much faster than metals do when subjected to the same thermal loading. Since very few joints operate at constant temperatures, thermal expansion or contraction is virtually universal. This will affect clamp load. However, this is only a problem if the application uses materials with dissimilar expansion rates and the temperature change is significant. Creep Rate Under load or heat all plastics will creep, or permanently deform. Creep will, in turn, cause a loss in clamp load. The chart at left demonstrates the loss of clamp load, at a stable temperature, over 64 hours for a #8 PLASTITE fastener driven into acetal resin. However, creep can be compensated for in joint design through a variety of methods. See page 8 for more details

6 Installing a Threaded Fastener in Plastics 1. Thread forming begins 2. Screw head in contact with plastic; clamp load generated 3. Strip-out torque level met or exceeded; boss damage occurs Torque 1. strip/failure torque clamping load 2. Penetration Depth 3. forming torque Thread forming and Stripping Torque Because friction increases as penetration increases, the differential between the forming torque and the strip (failure) torque must be maximized. Proper seating torque varies from application to application, so contact a STANLEY Engineered Fastening applications engineer for assistance. Torque (lbs.in) safety margin clamp forming strip (10 lbs.in) seating drive (5 lbs.in) strip (28 lbs.in) seating drive (7 lbs.in) Drive-to-Strip Ratio As demonstrated in the chart to the left based on testing the fastener for plastic has a much higher driveto-strip ratio, so the joint is less likely to be damaged during installation. The standard screw has a safety margin of only 3.5 lbs.in. The special fastener for plastic has a safety margin of 12 lbs.in. Note: The chosen seating torque was 65% of the failure torque, based on testing. Standard Fastener 2:1 strip-to-drive ratio Special Fastener for Plastic 4:1 strip-todrive ratio Influence of Driver Speed Increased drive gun speed can negatively affect the quality of the joint. During installation, as the RPMs increase, so does the amount of heat that is generated. Too much heat can break down the plastic and lower the failure torque level. Determining Proper Seating Torque STANLEY Engineered Fastening can run complete tests on your application to determine your optimal fastening solution, including fastener selection, joint design and seating torque. For a recommendation on how to run your own tests to determine proper seating torque, please see page

7 Design Issues and Fastener Selection There are several factors which can affect a fastener s ability to achieve satisfactory performance, including: Pilot hole diameter Length of engagement Boss design Though product design may dictate certain restrictions, laboratory testing will determine the proper combination of these factors for your application. Thread Engagement & Pilot Hole Diameter Thread engagement is the amount of flank depth that is filled by the application material. It is often expressed as a percentage. A hole diameter equal to the major diameter of the s would have a engagement of 0%. In moderately stiff materials, you should start with a hole size that provides 75% to 80% engagement. A hole that creates a engagement of over 100% does not improve performance. It will, however, increase required drive torque, because the walls of the hole must expand to make room for the screw. If the hole size is fixed, you will need to adjust the style or length of engagement to reach the appropriate performance requirements. Each fastener for plastics has its own parameters. For optimal performance, contact a STANLEY Engineered Fastening applications engineer for assistance. length of engage. lead s Length of Engagement Length of engagement is the measurement of full-sized fastener s engaged in the nut material. The length of the lead (usually about one-half the fastener diameter) is not counted in the length of engagement, since its reduced size minimizes any performance benefits. Length of engagement is often expressed in relationship to the nominal diameter of the screw; e.g. 2 to 2-1/2 diameters of engagement. CB d Boss Design Drafted holes ease molding in thermoplastics, but can affect engagement. Always utilize the minimum amount of draft possible to retain good mold function. Generally, the nominal hole size (hø) is calculated at a depth equal to half of the fastener s total length of engagement (L), not including the counterbore. Follow the specific boss design recommendations listed for each ed fastener. hø ½L L

8 Design Issues and Fastener Selection Compensating for the Effects of Creep in a Joint As stated previously, under load or heat, all plastics will creep. There are several methods to compensate for, or reduce, the effects of creep in a joint. Reduce the stress at the bearing surface by one or more of the following: increase the fastener head diameter add a flat washer reduce the clearance hole diameter reduce initial clamp load at assembly Add a spring element to the joint such as a helical and flat washer combination Add a metal sleeve in the clamped component to carry some of the clamp load Use a shoulder bolt to transfer the load to the nut member Increase stiffness of plastic by adding a filler or changing the base resin Testing to Determine Proper Seating Torque The following are general recommendations only. Torque Torque 1. Time Through Hole Signature Curve Time Blind Hole Signature Curve 1 Peak Drive Torque: level at which the materials are drawn together and the fastener seats 2 Ultimate Torque: level at which the joint fails; usually from strip-out 1. Gather enough sample applications to generate a statistically significant sampling a minimum of 30 per specific joint condition. These samples must include all components in the joint stack-up such as clamping components, nut members and fasteners. 2. Use a drive gun that can torque the fasteners to failure and has the same RPM as the drive gun that will be used in production. 3. Use a torque measuring device and a strip chart or graph and capture the peak drive torque and ultimate torque values. Drive the fasteners to failure. Calculate the average of the peak drive values and of the ultimate torque values. 4. Next calculate the average of these two resulting values. This is the target seating torque. Factor a value of ±10% for gun accuracy. Compare this torque window to +3SD (standard deviation) of the average drive torque value and -3SD of the average ultimate torque value. If there is no overlap of the two regions, the torque window will allow the fasteners to be seated without failure at assembly. If there is overlap in either of the two regions, a redesign of the joint is warranted. For assistance, please contact a STANLEY Engineered Fastening applications engineer

9 Selecting the Right Threaded Fastener The following chart is intended only as a starting point in the selection of fasteners. The fastener must be matched to the properties of the material. Drive to strip ratios, clamp retention, and other performance issues are directly affected by the fastener you choose. Please contact a STANLEY Engineered Fastening applications engineer for assistance in selecting the optimum fastener for your design. Thermoplastics ductile moderate Included Materials Flexural Modulus (PSI) Fastening Solution Polyethylene (PE) 150,000 Delta PT fastener, PT fastener, or Polypropylene (PP) 200,000 DST fastener Polycarbonate (PC) 340,000 ABS, 0-20% glass fill 350,000 Polyamide 66 (PA) 350,000 Acetal (AC) 400,000 Polystyrene (PS) 430,000 Polypropylene, 40% talc fill (PP40) 500,000 Polypheylene Sulfide 550,000 ABS, 20% glass fill 650,000 Polyamide 66, 12% glass fill 800,000 Polycarbonate, 20% glass fill (PC20) 850,000 Delta PT fastener, PT fastener, twin helix PLASTITE fastener, or DST fastener Delta PT fastener, twin helix PLASTITE 48 fastener, or PT fastener stiff Polycarbonate, 30% glass fill (PC30) 1,100,000 Polybutylene Terephthalates 30% glass fill (PBT30) 1,100,000 Polyamide 66, 30% glass fill (PA30) 1,200,000 Delta PT fastener, single-helix PLASTITE 48 or 45 fastener, or PT fastener Liquid Crystal Polymer (LCP) 1,400,000 Thermosets Polyphenylene Sulfide, 40% fill (PPS40) 1,700,000 Phenolic, 20% glass fill 1,750,000 Polyester, 50% glass fill 2,100,000 Duro PT -cutting fastener Type of Application Fastening Solution All Plastics Plastic or other materials to thin metal Molded assemblies Powergrip fasteners PlasTORX fasteners

10 Delta PT Thread Forming Fasteners Delta PT fasteners are engineered to provide maximum performance in a wide range of thermoplastics. The improved design results in a stronger fastener that creates optimal material flow during installation, providing higher performance, better clamp loads and increased joint life. optimal material flow engineered flank geometry Delta PT Fastener Key Advantages Provides optimal performance in all types of thermoplastics Provides increased torsional and tensile strength over PT fasteners Provides high strength and in-place reliability Can achieve higher clamp loads and seating torques Specifications s: Delta PT (1.4mm 7.0mm); other sizes may be available Head Styles: Can be used with any head design Specials: Shoulder screws, sems, double end studs, collar studs; others as required Drive Systems: TORX PLUS Drive is recommended to facilitate the proper amount of torque transfer required for forming s. Other styles also available. Features & Benefits Flank geometry engineered to provide better material flow during installation Provides high flank engagement Can achieve higher clamp loads and seating torques Optimizes material flow May permit use of shorter fasteners and/or smaller diameters, if necessary Larger fastener cross-section Increases shear area and fastener strength Offers increased fatigue life Provides increased torsional and tensile strength Optimized pitch Allows high clamp load with smaller contact pressure Minimizes radial stress Applications Thermoplastics with a flexural modulus up to 1,400,000 p.s.i

11 Delta PT Thread Forming Fasteners Dimensional Data *PT fastener standards are true metric sizes. p mø Mø Nom. Metric p Thread Pitch Mø Major Dia. mø Minor Dia. Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Delta PT Increased Strength Boss Design Recommendations The criteria for optimum hole diameter is to obtain the maximum clamp load during the installation process. A good starting point in determining the proper hole diameter is d = 0.8 x d 1 Delta PT fastener PT fastener R = 0.1 Cycle stress; breakage of the fastener cross section With its extended core diameter and optimum design, the Delta PT fastener offers a longer fatigue life than the PT fastener. The Delta PT design provides better engagement and, therefore, better conditions against stress fractures of the flank. Specific applications will require some modifications to allow for the flexural modulus of the material, molding conditions, mold tool design, feed distance from gate, weld lines, structural heterogeneity and amount of reground material. In order to ensure optimal performance, we recommend testing on initial samples. Please contact a STANLEY Engineered Fastening applications engineer for assistance. The chart above demonstrates that the Delta PT fastener provides greater resistance against screw breakage than the PT fasteners under in-service loads

12 PT Thread Forming Fasteners With a high profile and recessed root, the PT fastener provides increased engagement with minimal stress on the boss. It provides optimal performance in a wide range of thermoplastics. narrow pitch 30 profile recessed root PT Fastener Key Advantages Optimizes performance in all types of thermoplastics Provides maximum resistance to back-out and pull-out Minimizes boss failure Increases product reliability Specifications s: K15 K100 in diameter up to 127mm under head Head Styles: Can be used with any head design Specials: Shoulder screws, sems, double end studs, collar studs; others as required Drive Systems: TORX PLUS Drive is recommended to facilitate the proper amount of torque transfer required for forming s. Other styles also available. Applications Thermoplastics with a flexural modulus up to 1,400,000 p.s.i. Features & Benefits Narrow 30 profile minimizes radial expansion and stress in boss Permits use of thinner bosses, which can reduce cycling times and material usage Reduces back-out caused by relaxation Increases load-carrying capability through increased engagement Can be used in repeat assembly operations Optimum pitch allows deeper engagement Provides increased pull-out values Optimizes non-reversibility Balances load ratio between plastic and screw Recessed root allows optimal material flow Minimizes installation torque Improves clamp load Minimizes potential of boss cracking Round body evenly distributes surface contact between application and screw Improves load ratio Reduces high points of stress on the boss Through hardened to Rc

13 PT Thread Forming Fasteners p mø Mø Dimensional Data Nom. Metric p Thread Pitch *PT fastener standards are true metric sizes. Mø Major Diameter mø Minor Diameter K K K K K K K K K K K Hole s per Percentage of Thread Engagement 100% 90% 80% 70% 60% 50% 40% mm in. mm in. mm in. mm in. mm in. mm in. mm in. K K K K K K K K K K K

14 PT Thread Forming Fasteners Laboratory testing and service applications have produced the general recommendations shown here. Specific applications may, however, require some modifications to allow for: molding conditions weld lines mold tool design structural heterogeneity amount of reground material feed distance from gate In order to ensure optimal performance, we strongly recommend testing on initial samples. counterbore depth 0.3d to 0.5d boss ø 1.8d to 2.5d d Counterbore The width of the counterbore should be equal to the major diameter of the screw (d). The height of the counterbore should be 0.3 to 0.5 times the nominal screw diameter. PT Fastener Boss Design Recommendations Material Hole Dia. Boss Dia. Length of Engagement ABS (acrylonitrile) 0.80 x d 2.00 x d 2.00 x d ASA (acrylonitrile styrene acrylic) 0.78 x d 2.00 x d 2.00 x d Nylon: PA6 (polyamide) 0.75 x d 1.85 x d 1.70 x d Nylon: PA-GF x d 2.00 x d 1.90 x d Nylon: PA x d 1.85 x d 1.70 x d Nylon: PA6.6-GF x d 2.00 x d 1.80 x d PBT (polybutylene terephthalate) 0.75 x d 1.85 x d 1.70 x d PBT-GF x d 1.80 x d 1.70 x d PC (polycarbonate) 0.85 x d 2.50 x d 2.20 x d PC-GF x d 2.20 x d 2.00 x d PE soft (polyethylene) 0.70 x d 2.00 x d 2.00 x d PE hard (polyethylene) 0.75 x d 1.80 x d 1.80 x d PET (polyethylene terephthalate) 0.75 x d 1.85 x d 1.70 x d PET-GF x d 1.80 x d 1.70 x d POM acetal 0.75 x d 1.95 x d 2.00 x d PP (polypropylene) 0.70 x d 2.00 x d 2.00 x d PPO (polyphenylene oxide) 0.85 x d 2.50 x d 2.20 x d PS (polystyrene) 0.80 x d 2.00 x d 2.00 x d PVC hard (polyvinyle chloride) 0.80 x d 2.00 x d 2.00 x d SAN (styrene acrylonitrile) 0.77 x d 2.00 x d 1.90 x d hole ø 0.70d to 0.85d Boss Design Example Material: ABS To calculate boss size based on fastener size: Screw size: K40 Major diameter: 4mm Boss O.D. = 2 x screw dia. 2 x 4mm = 8mm Boss I.D. = 0.8 x screw dia. 0.8 x 4mm = 3.2mm Min. length of engagement = 2 x screw dia. 2 x 4mm = 8mm To calculate screw size based on (predetermined) boss size: Boss O.D.: 8mm Boss I.D.: 3.2mm Screw dia. = Boss O.D. 2 8mm 2 = 4mm

15 DST Thread Forming Fasteners The high height and wide spacing of the DST (Dual-Spaced Thread) fastener allows increased engagement in softer thermoplastics, increasing resistance to pull-out and improving product performance. two profiles high height DST Fastener various point styles available Key Advantage Performs well in softer thermoplastics Features & Benefits High with a 30 flank angle to reduce radial stress in the boss Requires lower driving torque Reduces cracking of boss Allows use of smaller bosses Specifications s: #5 to 5/16 (metric 3.5 8) Head Styles: Pan, hex, flat, oval, hex washer Point Styles: Blunt, gimlet, pilot Drive Systems: Can use any system, including TORX PLUS Drive Smaller minor diameter than standard screws allows greater shear area Increases engagement Increases resistance to pull-out Shank slot for -cutting can be added. Please contact a STANLEY Engineered Fastening applications engineer for appropriate dimensional information. Applications Thermoplastics with a flexural modulus up to 600,000 p.s.i

16 DST Thread Forming Fasteners Dimensional Data Inch Dimensional Data Metric Screw p Thread Pitch (per in.) Hø High Thread Dia. Lø Low Thread Dia. mø Ref. Minor Dia. Screw p Thread Pitch Hø High Thread Dia. Lø Low Thread Dia. mø Ref. Minor Dia. # # # p # # # mø Lø Hø # /4" /32" /16" Boss Design Recommendations boss O.D. Hø d The recommended hole size (d) can be found in the chart to the right. The length of engagement (l e ) should be 3 times the high diameter (see chart above). Counterbore depth is 1 to 2 times the pitch length (see chart above). Counterbore depth is equal to the high diamter (Hø). The boss O.D. should be at least 2 times the high diameter. 2p l e Recommended Hole s Screw (inch) Hole (d) (in.) #5.099 #6.110 #7.125 #8.128 # # # /4".201 9/32".234 5/16".250 Screw (metric) Hole (d) NOTE: Recommended hole sizes for DST -cutting fasteners are not shown. Please contact a STANLEY Engineered Fastening applications engineer for assistance

17 PLASTITE 48 Thread Forming Fastener The PLASTITE 48 fastener combines a unique TRILOBULAR body with a 48 profile to maximize performance and reliability. Two forming styles are available to meet the specific requirements of a wide range of thermoplastics. steeper helix angle 48 profile shallower helix angle Trilobular shank Twin-Helix Style Single-Helix Style PLASTITE 48 Fasteners Key Advantages Reduces possibility of boss failure Increases product reliability Eliminates need for inserts and lock washers Specifications s: #00 5/16"; other sizes may be available upon request Head Styles: Can be used with any external or internal head designs; pan, hex washer, and flat styles standard Drive System: Can use any system, including TORX PLUS Drive Finish: As required Applications Twin Helix Style: Thermoplastics with a flexural modulus up to 850,000 p.s.i. Single Helix Style: Thermoplastics with a flexural modulus between 850,000 p.s.i. and 1,400,000 p.s.i. Features & Benefits Trilobular configuration allows displaced material to cold flow back into relief areas Minimizes radial stress relief areas Reduces possibility of boss failure Eliminates need for inserts and lock washers Allows design of thinner bosses forming lobes 48 profile allows s to penetrate deeply into plastic material Generates strong mating s Resists vibration loosening Reduces probability of strip-out and pull-out Twin lead design and steep helix angle provides greater shear area in softer plastics (with a flexural modulus up to 850,000 p.s.i.) Increases holding power Allows faster seating of fastener Single lead design and narrow helix angle lowers drive torque and failure torque in stiffer thermoplastics (with flexural modulus between 850,000 and 1,300,000 p.s.i.) Creates less stress on the boss

18 PLASTITE 48 Thread Forming Fastener D C C dimension measured with Tri-Flute Micrometer D diameter measured with Standard Micrometer Dimensional Data Inch s Nom. Thread Pitch (per inch) C Dimension max-min (in.) D Dimension max-min (in.) Screw Length Tolerance under 3/4" over 3/4" (in.) (in.) # ±.015 ±.015 # ±.015 ±.015 # ±.030 ±.030 # ±.030 ±.030 # ±.030 ±.030 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 1/4" ±.050 ±.050 5/16" ±.050 ±.050 Dimensional Data Metric s* Nom. Thread Pitch C Dimension max.-min. D Dimension max.-min. *soft converted metric sizes Screw Length Tolerance under 19.05mm * Plastite 48 fasteners are not available in true metric sizes. The chart above provides nominal inch dimensions converted to millimeters. over 19.05mm ±0.38 ± ±0.38 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±0.76 ± ±1.27 ± ±1.27 ±

19 PLASTITE 48 Thread Forming Fastener Hole s per Percentage of Thread Engagement 100% 90% 80% 70% 60% 50% 40% in. mm in. mm in. mm in. mm in. mm in. mm in. mm # # # # # # # # # # # # /4" /16" Boss Design Recommendations The length of engagement (L) should be 2 to 3 times the fastener s C dimension. Testing should be done to determine optimal engagement on any application with a lower length of engagement. The nominal hole size (hø) must be established based on the amount of engagement (see chart above). For optimum performance, the hole size should provide a minimum 70% engagement. boss O.D. CB w CB d hø 1 / 2 L L add l hole depth for length tolerance The outside diameter of the boss (boss O.D.) should be 2.5 to 3 times the nominal diameter of the screw (C dimension). The boss height should not exceed 2 times the boss O.D. The counterbore width (CB w ) should be slightly larger than the C dimension. Its depth (CB d ) should be 1/4 to 1/2 the pitch

20 PLASTITE 45 Thread Forming Fastener The PLASTITE 45 fastener is designed to facilitate forming in lesscompressable plastics while providing high resistance to strip-out and pullout. It has smaller root and major diameters than a 48 PLASTITE, so it can be used in smaller bosses. 45 profile Trilobular configuration PLASTITE 45 Fastener Key Advantages Can be used in smaller bosses than PLASTITE 48 fasteners Increases product reliability Lowers required drive torque when fastening stiffer thermoplastics Specifications s: #2 3/8" (metric sizes 2 8); other sizes may be available upon request Head Styles: Can be used with any external or internal head designs; pan, hex washer, and flat styles standard Drive System: Can use any system, including TORX PLUS Drive Finish: As required Applications Engineering-grade thermoplastics (with a flexural modulus over 850,000 p.s.i.) Features & Benefits Trilobular configuration allows displaced material to cold flow back into relief areas Minimizes radial stress Reduces possibility of boss failure Eliminates need for inserts and lock washers Allows design of thinner bosses relief areas forming lobes 45 profile allows s to penetrate deeply into plastic material Generates strong mating s Resists vibration loosening Increases resistance to strip-out Achieves wide differentials between drive and fail torque Single lead design and narrow helix angle lowers drive torque and failure torque in thermoplastics with a flexural modulus over 850,000 p.s.i. Creates less stress on the boss

21 PLASTITE 45 Thread Forming Fastener C dimension measured with Tri-Flute Micrometer D C D diameter measured with Standard Micrometer Dimensional Data Inch s Nom. Thread Pitch (per inch) C Dimension max.-min. (in.) D Dimension max.-min. (in.) Screw Length Tolerance under 3/4" over 3/4" (in.) (in.) # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 # ±.030 ±.050 1/4" ±.050 ±.050 9/32" ±.050 ±.050 5/16" ±.050 ± /64" ±.050 ± /32" ±.050 ±.050 3/8" ±.050 ±.050 Dimensional Data Metric s Nom. Thread Pitch C Dimension max.-min. D Dimension max.-min. Screw Length Tolerance under 19.05mm over 19.05mm ±.08 ± ±.08 ± ±.08 ± ±.08 ± ±.08 ± ±.08 ± ±1.3 ± ±1.3 ± ±1.3 ± ±1.3 ±

22 PLASTITE 45 Thread Forming Fastener Hole s per Percentage of Thread Engagement Inch s 100% (in.) 90% (in.) 80% (in.) 70% (in.) 60% (in.) / / / / / / Metric s 100% 90% 80% 70% 60% 2 x x x x x x x x x Boss Design Recommendations boss O.D. CB w CB d The length of engagement (L) should be 2 to 3 times the fastener s C dimension. Testing should be done to determine optimal engagement on any application with a lower length of engagement. hø 1 / 2 L L The nominal hole size (hø) must be established based on the amount of engagement (see chart above). For optimum performance, the hole size should provide a minimum 70% engagement. add l hole depth for length tolerance The outside diameter of the boss (boss O.D.) should be 2.5 to 3 times the nominal diameter of the screw (C dimension). The boss height should not exceed 2 times the boss O.D. The counterbore width (CBw) should be slightly larger than the C dimension. Its depth (CB d ) should be 1/4 to 1/2 the pitch

23 Duro PT Thread Cutting Fasteners The Duro PT cutting fastener is engineered to meet the demanding requirements of thermoset plastics, easing assembly and ensuring a strong, reliable joint to maximize assembly performance. recessed root 30 profile optimal pitch shank slot Duro PT Thread Cutting Fastener Key Advantages Cuts s in stiffer plastics Minimizes installation torque Maximizes assembly performance Specifications s: S22 to S80 in diameter; up to 152mm under head. Other sizes may be available upon request. Head Styles: Pan, flat, hex, round washer, hex washer, oval, button head, fillister Specials: Shoulder screws, sems, double end studs, collar studs; others as required Drive Systems: TORX PLUS Drive System is recommended to facilitate the proper amount of torque transfer required for cutting s. Other styles are available. Features & Benefits Asymmetrical 30 profile, inclined towards load surface to increase friction (FR) between the application and the fastener Reduces radial stress Reduces back-out caused by relaxation ß Increases strip resistance C L N Eliminates need for supplementary locking devices Optimal pitch for deeper engagement Increases pull-out strength Increases resistance to vibration loosening Increases load-carrying capability Recessed root provides space for displaced material Minimizes installation torque Minimizes risk of clogging and galling of s during assembly Shank slot minimizes chip production Through hardened to Rc F R = µ x N N=C L /cosß Applications Thermoset plastics

24 Duro PT Thread Cutting Fasteners Dimensional Data p mø Mø Nom. Metric Thread Pitch Mø Major Diameter mø Minor Diameter S S S S S S S S S Hole s per Percentage of Thread Engagement 100% 90% 80% 70% 60% 50% 40% mm in. mm in. mm in. mm in. mm in. mm in. mm in. S S S S S S S S S Suggested Thread Engagement Based on testing and past performance, a engagement of 50% to 60% is recommended. For optimal fastener performance, please contact a STANLEY Engineered Fastening applications engineer. See following page for boss design recommendations

25 Duro PT Thread Cutting Fasteners Boss Design Recommendations Laboratory testing and service applications have produced the general recommendations shown. Specific applications may, however, require some modification in order to allow for: 2.9d to 2.63d w 120 x molding conditions type of filler db L mold tool design type of resin material density L c Determining Optimum Boss & Hole s A hole diameter of.85d to.89d is permissible for most thermoset applications. In order to properly determine boss and hole sizes, it is recommended that testing be done on several different hole sizes. This will allow you to determine the optimum drive-to-strip ratio that is required for your application. Boss Hole Diameter (db) d = nominal screw diameter.85d.86d.87d.88d.89d mm in. mm in. mm in. mm in. mm in. S S S S S S S S S Boss Outer Diameter (O.D.) d = nominal screw diameter.85d.86d.87d.88d.89d mm in. mm in. mm in. mm in. mm in. S S S S S S S S S d = nominal screw diameter Boss Counterbore High tightening torques and large tensile stresses may cause a coneshaped expansion and failure at the bottom of the boss. Designing the boss with the appropriate counterbore (CB) reduces edge stress and alleviates cracking. CB depth: x = 0.5d CB width: w = 1.08 x d Length of Engagement The length of engagement (L) should be 2 to 3 times the nominal screw diameter. This calculation should exclude counterbore depth. Chip Space Depth The depth of space (Lc) for chips removed during cutting operations should be between 0.8 and 1.2 the nominal screw diameter. NOTE: The information in this manual is not to be considered a specification

26 Powergrip Fasteners for Layered Assemblies Ideal for attaching soft materials, such as plastics and elastomers, to a single thickness of sheet metal, Powergrip fasteners maintain the integrity of the soft material while providing resistance to strip-out and loosening. speciallydesigned shoulder serrations and undercut Powergrip Fastener Key Advantages Overcomes loosening in metal to plastic/elastomer applications Prevents soft material from being crushed during assembly Can be used in a variety of materials, soft or brittle, where there is a chance that cracking or crushing of the overlay material may occur Specifications s: M3 M8 (#4 3/8") Thread Styles: Type CA s are recommended for maximum engagement; others as required Head Styles: Hex washer, pan, round, truss, hex Drive Styles: TORX PLUS Drive; also cross, slotted, and hex Applications Soft materials such as plastic, rubber and elastomers to sheet metal Features & Benefits Individually engineered to meet the unique requirements of each application Can be used in a variety of materials, soft or brittle, where there is a chance that cracking or crushing of the overlay material may occur Specially designed shoulder designed to match the thickness of the soft material in each application Prevents soft material from being crushed during assembly Serrations and a small undercut on the bottom of shoulder to decrease the distance between the last and the shoulder Increases engagement Increases strip-out resistance Prevents vibration loosening Increases torque resistance Provides tight, uniform joint

27 PlasTORX Fasteners for Plastic Assemblies Developed to be molded into plastic and replace metal stamping and fastener assemblies, PlasTORX studs are engineered to provide high resistance to rotation and pull-out, ensuring a high-performance assembly. Its hex-lobular design helps reduce stress risers, so it can be used in materials susceptible to cracking or breaking. TORX configuration flange on top of head enhances performance hex-lobular design ed shaft for nut assembly PlasTORX Fastener Key Advantages Molded directly into application which increases assembly efficiency Provides maximum resistance to rotation and pull-out Can be used in materials susceptible to cracking Specifications s: M4 M12 (#8-1/2") Lengths: Per customer design Thread Styles: Machine screw; others as specified Specials: Completed assemblies available Applications Injection-molded thermoplastics and rubber Features & Benefits Hex-lobular TORX configuration allows deep lobe engagement Increases torsional resistance Increases pull-out resistance Reduces stress risers Flange on top of head enhances performance Increases pull-out resistance Threaded shaft for seating nut member Designed to be molded directly into component or carrier strips, allowing multiple fasteners to be installed at one time Reduces assembly time Reduces part numbers and associated costs Reduces overall costs

28 PlasTORX Fasteners for Plastic Assemblies A Ref. B C D ø of ed shaft Contour may vary between lobes within specifed dimensions. Dimensions shown are for low carbon steel fasteners. For other materials or modified designs, contact a STANLEY Engineered Fastening applications engineer. Performance is determined by application material. ø E min. bearing surface Dimensional Data Metric s Thread A ref. B ±0.13 C ±0.25 D max. E min. Min. Molded Mat l Width Min. Molded Mat l Height (B + 25%) M M M M M M Dimensional Data Inch s Thread A ref. B ±.005 C ±.010 D max. E min. Min. Molded Mat l Width Min. Molded Mat l Height (B + 25%) # # / / / /

29 Other Threaded Fasteners for Plastics Trilobular body unique profile PUSHTITE & PUSHTITE II Thread Forming Fasteners The unique profile of PUSHTITE fasteners allows them to be simply pressed into place, virtually eliminating strip-out during initial assembly and providing high pullout strength. Trilobular shape minimizes stress on the boss Screws can be removed and reinserted if necessary, or can be made tamper-resistant Can be gang-driven, which can cut costs Allows displaced air to escape during insertion to prevent pneumatic failure of boss narrow profile recessed root optimal pitch 5 larger pitch length multiple flutes asymmetrical profile BF-Plus Thread Cutting Fasteners The unique cutting flutes of the BF-Plus fastener were designed to provide deep, fully-cut mating s with minimal contamination. It helps ensure reliable fastening in harder plastics. Multiple flutes for cutting extend through first full diameter to reduce radial stress and boss damage 5 reverse angle of flutes retains chips to minimize contamination 48 profile with extended height, combined with a longer pitch length, increases flank and shear area to increase pull-out resistance and strip-out resistance Duro PT Thread Forming Fasteners Duro PT forming fasteners are engineered to meet the unique requirements of reinforced thermoplastics and light alloys. Asymmetrical 30 profile reduces radial stress and minimizes installation torque Allows deep engagement to increase pull-out strength and increase resistance to vibration loosening Eliminates need for supplementary locking devices Recessed root provides space for displaced material, minimizing risk of clogging and galling during assembly narrow profile large minor diameter Hi-Wide Thread Forming Fasteners Large minor diameter 40, 45, or 48 profiles available Wide spacing for greater shear area to increase pull out resistance Thread forming and -cutting styles are available Variety of point styles available for forming screws

30 TORX PLUS Drive System The TORX PLUS Drive System is the ideal drive system for screws for plastics, since it provides optimum torque transfer, even when forming or cutting s in reinforced plastics. Its unmatched ability to increase productivity by outperforming competing drive systems can lower assembly costs. large cross-sectional area elliptically-based gemometry 0 drive angle broad contact surface TORX PLUS Drive System Key Advantages Allows optimum torque transfer for forming or cutting s in plastic applications Features & Benefits Unique, elliptically-based geometric configuration to maximize engagement between driver and fastener Specifications Drive s:1ip 100IP (recess) to fit screw sizes M0.9 M24 (#0 1") Styles: Internal, external, lowprofile external, tamper-resistant, TORX PLUS Drive/external hex or TORX PLUS Drive/slotted Drive Tools: TORX PLUS Drive tools fit both inch and metric fasteners. Standard and special tooling is available from over 3,000 outlets around the world. For more information, please contact STANLEY Engineered Fastening. True 0 drive angle virtually eliminates the radial forces that cause stress on fastener recesses with vertical walls Allows optimum torque transfer, even in plastics reinforced with nylon or carbon fibers Vertical sidewalls completely enclose the driver tip, reducing tool slippage and virtually eliminating camout Prevents damage to the fastener and surrounding surfaces, which often occurs with cross recess fasteners Eliminates the debris camout can create, which can damage sensitive applications Minimizes damage to application Higher torque removal capability than any other drive system Helps minimize damage to boss from removal and reinsertion of the screw Improved fit between fastener and tool minimizes wear on the drive bit Drive bit life lengthened as much as 12 times Downtime and costs are reduced since significantly fewer drive bit changes are required